1. Field of the Invention
The present invention relates to a inspection method and apparatus for continuity inspection of electronic components used in electronic equipment.
More specifically, it relates to an inspection method and apparatus for quick and low-cost continuity inspection of semiconductor components of a printed circuit board that has a high-density wiring pattern and of semiconductor components that have bump electrodes.
2. Description of Related Art
A printed circuit board is has a wiring pattern that is made of a foil of copper, silver or the like on top of either a board that is rigid or flexible, this type of board being widely used for the internal components of electronic equipment.
The continuity inspection of various parts of such a printed circuit board is an important process from the standpoint of assuring product reliability.
At present, with the reduction in size of electronic equipment, advances are being made in the achievement of high-density printed circuit boards, this bringing with it wiring patterns that are becoming finer and finer.
In the past, continuity inspection of printed circuit boards was performed by causing an inspection probe to make contact with each of the terminals formed in the wiring pattern of the printed circuit board.
As printed circuit board density becomes greater, however, many high-cost micro-inspection probes are required for continuity inspection of a printed circuit board, thus resulting in an increase in the cost of inspection
To accommodate the problem of higher density printed circuit boards, the Japanese Unexamined Patent Publication (KOKAI) Nos. 3-283599 and 6-45718, as shown in FIG. 4, propose printed circuit board continuity inspection methods which use a redundant part 31, which has an inspection pad and which can be removed after use in a continuity inspection.
While prior art printed circuit board continuity inspection methods of Japanese Unexamined Patent Publication Nos. 3-283599 and 6-45718 enable the achievement of a sufficient inspection pad size, regardless of the high density of the printed circuit board, because these methods require that a redundant part 31 be provided on the printed circuit board, they involve the same problem of a rise in cost as noted for the case of using a microprobe for inspection.
For the continuity inspection of printed circuit boards that are becoming denser and denser, the approaches in the past have been those of using high-cost microprobes or providing the printed circuit board with a redundant part using for continuity inspection. Both of these methods, however, lead to significant increases in cost.
An object of the present invention is to provide a continuity inspection method and apparatus which solve the problems involved with the prior art as described above, and which can accommodate electronic components, and in particular high-density printed circuit boards.
Another object of the present invention is to provide a printed circuit board that is suitable for the above-noted method.